Problem: Multiply. $0.5 \times 3.3 = $
Answer: $5 \times 33$ and $0.5 \times 3.3$ multiply the same digits in the same order. So, the product of both problems will also have the same digits in the same order. Let's multiply $5 \times 33$. Then we can estimate to place the decimal point in the product of $0.5 \times 3.3$. $\begin{aligned} 33&\\ \underline{ \times 5}&\\ 15}\\ \underline{+150}}\\ 165 \end{aligned}$ Let's estimate to place the decimal in $0.5 \times 3.3$. $\begin{aligned} 0.5 \times 3.3 &\approx 0.5 \times 3\\\\ &\approx \dfrac{1}{2}\times \dfrac{3}{1}\\\\ &\approx \dfrac{3}{2}\\\\ &\approx 1.5 \end{aligned}$ Where can we place the decimal in $165$ to get a product close to $1.5$ ? $0.5 \times 3.3 = 1.65$